4.6 sohc question?

[s3c2n01]

I have a 98 gt npi. i swapped the cams for the pi and slammed the pistons on the pass side. with the exhaust valves.

so here is my problem.
i have 03 cobra pistons and 5140 i beam rods and 03 cobra crank. i was wandering if anyone knows what the compression would be with pi heads.
i know with stock pistons and pi heads it jumps to 10.5.1 i am running vortech s- trim 6-8 lbs with Anderson Ford power pipe will add 2 or 3 more pounds of boost.

or where i can find out the info.

thanks chris

 

[Thomas_W]

imma go out on a limb and say upper 9's lower 10's w/o knowing right off the top of my head the piston dish size..... whats the dish size of those pistons?

 

[s3c2n01]

not 100% sure. i think the stock pistons in the 03 cobra on the manley website is 18cc.

 

[ripper]

I have forged probes and mine are 18cc. On the pi motor my comp is 9:1. Are you gonna do h/c/i along with the r/a? Also i thought pi cams would clear flathead pistons on a non pi motor :dunno:

 

[voidfinger]

they do, timing must have been way way off.

Many people do the head and cam swap and have no problems at all, there is a good amount of room to go.
Did the timing marks read right?

 

[ripper]

Thats what i thought. Maybe he stretched a piston or rod.

 

[s3c2n01]

i had the timing was off. i have had someone from blackmustangclub.com tell me it should be around low 9 or mid 9.

i am off to rebuild my motor for the s trim and gas . wish me luck i will keep every one posted on this.


thanks for the info guys.

 

[s3c2n01]

they do, timing must have been way way off.

Many people do the head and cam swap and have no problems at all, there is a good amount of room to go.
Did the timing marks read right?

pi cams in npi heads. i am trying to see if it would be safe for pi heads on a npi motor with 03 cobra pistons and s trim and power pipe.
without out pulling a butt load of timing and not running race gas all the time. daily driver for now